I just noticed that the First Sergeant has, what I would call today, a "hybrid rank." The rank of First Sergeant is 3 strips up, and 3 stripes down. You can see that he has three up and one down, which normal is the rank of a Staff Sergeant, two ranks lower than a First Sergeant. But, he also has the diamond in the center, this is the identifier that differentiates a Master Sergeant (also 3 up and 3 down) from a 1st Sergeant (3 up, 3 down + the diamond).
In my Grandfather's memoirs he writes a lot of brevet ranks wherein someone of lower rank is recognized as a higher rank for functional purposes but hasn't yet received the formal promotion. This was a necessity of war when hundreds of thousands of men were drafted and mobilized in a short time and as new units were formed men had to be promoted into the leadership slots.
This unit, the 132nd Infantry Regiment, 33rd Infantry Division, was mobilized in 1941, almost a full year before Pearl Harbor. This photo was taken in early 1942 as the already mobilized Regiment was flooded with new draftees. My Grandfather joined a year before Pearl Harbor as a Private, E-1 (Enlisted 1st level) and by 1944 he was an E-8 First Sergeant - a jump of 7 ranks in 3 years, almost unheard of today. Normally it takes 15 or 20 years or more to achieve the rank of First Sergeant. My Grandfather was also promoted to First Sergeant while only a Staff Sergeant and was later given the rank to match the job.
We saw the same with Colonel Custer - he was promoted to General (brevet) in the Civil War and reverted back to Colonel at the war's conclusion.
